Puzzlemania

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Across
  1. 6. the prime numbers having difference 2 are called _____
  2. 7. one added to the greatest seven digit number is equal to ______
  3. 8. the smallest whole number is _____
  4. 9. ____ is a factor of every number
Down
  1. 1. writing of numbers from greatest to smallest is called an arrangement in _____ order
  2. 2. 401 is the ____ of 400
  3. 3. A number for which the sum of all its factors is equal to twice the number is called a _____ number
  4. 4. numbers having more than two factors are called ____ numbers
  5. 5. two numbers having only one as a common factor are called _____ numbers
  6. 6. One million is equal to _____